The present invention relates generally to a modular system for introducing therapeutic or diagnostic devices, such as a blood filter, occluder, atherectomy device, stents, angiographic catheters, and pressure monitors to a vessel or cardiac tissue. More particularly, the system delivers the devices independently or in combination through a single incision on the vessel or cardiac tissue via one or more removably attached access ports and lumens.
During various cardiothoracic, pulmonary, and vascular surgeries, including coronary artery bypass grafting, heart valve repair or replacement, atrial or ventricular septal defect repair, angioplasty, atherectomy, aneurysm repair, and pulmonary thrombectomy, cannulation of a patient""s vessel(s) are often required to provide vascular access for delivery of various diagnostic and therapeutic devices. In a conventional approach, separate incisions are needed for introduction of each medical device. For example, during coronary artery bypass grafting (CABG) surgeries, cardiopulmonary bypass is established by cannulation of the aorta to provide circulatory isolation of the heart and coronary blood vessels. Two incisions on the aorta may be required, i.e., one for insertion of the arterial cannula and another for insertion of a balloon occluder to provide coronary isolation from the peripheral vascular system. When cardiac arrest is desired, a third incision may be required on the aorta to introduce a catheter for delivering cardioplegic solution to the coronary arteries. Additional incisions may be required for insertion of other devices, such as a blood filter, pressure monitor, or atherectomy device. Once the incisions are made on the aorta, the devices often remain in the aorta throughout the entire procedure despite only being used intermittently, e.g., the cardioplegia catheter.
Due to significant mortality and morbidity associated with conventional CABG surgeries from the use of cardiopulmonary bypass for circulatory support and the traditional method of access by median sternotomy, minimally invasive concepts recently have been adopted to make cardiothoracic procedures less invasive. Minimally invasive alternatives include the minimally invasive direct CABG procedure in which the operation is performed through minimal access incisions, eliminating cardiopulmonary bypass. The second alternative is to perform the procedure through minimal access incisions, and cardiopulmonary support is instituted through an extra thoracic approach, i.e., the port access approach. The third alternative is to perform the procedure on a beating heart which allows greater access for more extensive revascularization, i.e., the xe2x80x9coff pumpxe2x80x9d sternotomy approach. In any of the minimally invasive alternatives, the space allowed for multiple instrumentation and device insertion is limited.
The disadvantages associated with the conventional or minimally invasive approach are that (1) by having multiple devices inserted in the aorta, the space available for the surgeon to perform procedures is limited, and (2) the aorta is traumatized as a result of multiple incisions, which may result in aortic dissection, aortic wall hematoma, and/or embolization of calcium plaque from the aortic wall. The greater the aortic trauma, the higher the perioperative morbidity a patient will endure.
New devices or systems are therefore needed which provide access to a patient""s vessel and introduction of multiple diagnostic and therapeutic devices during cardiovascular procedures, thereby minimizing crowding caused by the multiple device insertions and trauma to the vessel wall.
The methods and systems of the present invention provide means of introducing a combination of multiple devices or instruments into a vessel through a single incision site, thereby reducing the number of incisions on the vessel and minimizing space crowding during vascular surgeries. More particularly, various devices and instruments can be inserted into the vessel through one or multiple lumens and access ports which are removably attached to a cannula in the modular access port systems, thereby minimizing the trauma of exchanging devices through the vessel wall. The methods and systems can be used in conventional or minimally invasive surgeries to provide any combination of the following functions: perfusion, drug delivery, fluid infusion, vessel occlusion, filtration, aspiration, blood sampling, venting, fluid diversion, venous return in cardiopulmonary bypass, atherectomy, fluid pumping, suturing, stapling, collagen or fibrin delivery, placement of pacing leads, use of angiographic catheters, angioplasty catheters, valvuloplasty catheters, electrode catheters, sizing tools, internal vessel segregating or isolating dams, endoscopic cameras, pressure monitors, shunts, stents, grafts, stent/grafts, vessel surfacing modalities, radioactive isotopes, graft delivery, and endoscopic devices. For example, devices traditionally introduced through the femoral artery (i.e., stents, atherectomy catheters, or angioplasty catheters) can also be introduced directly into the aorta, if deemed advantageous or beneficial to the patient.
In a first embodiment, the cannula has a lumen communicating between a proximal end and a distal end. The distal end is adapted for perfusion of blood, i.e. for use as an arterial cannula or venous return cannula in cardiopulmonary bypass. The proximal end is adapted for attachment to a bypass-oxygenator machine. A clip-on access port is removably attached to a distal region of the cannula. The access port has a lumen extending from a proximal end to a distal end. The proximal end of the port is adapted to receive medical devices. In certain embodiments, the access port can be attached to any standard arterial or venous cannula in any orientation. In other embodiments, the access port is attached to the cannula only in one orientation to ensure a desired relationship between the cannula and the access port.
In another embodiment, a second access port is removably mounted to the distal region of the cannula adjacent to the first access port, such that the ports are arranged at the vertices of a triangle. Having the triangular arrangement may be preferred in minimally invasive procedures where surgical space is limited. Alternatively, the second port is removably mounted to the first port, such that the ports and the cannula are arranged in a linear configuration. A hemostatic valve may be included in the lumen of either or both of the access ports. The distal ends of the cannula and/or the access ports may include a suture flange for securing the system onto the vessel.
In a first method to provide insertion of medical devices and cannulation of a vessel or cardiac tissue, the access port is attached adjacent the distal region of the cannula. The distal ends of the cannula and the access ports are inserted through an incision on the vascular or cardiac tissue. For example, to provide arterial cannulation for cardiopulmonary bypass, the cannula is inserted through an incision on the aorta. A medical device, such as a cardioplegia catheter, can be inserted through the proximal end of the access port and deployed in the aorta. When cardioplegia is no longer required, the catheter can be removed from the access port and another medical device, such as a pressure monitor can be inserted into the aorta through the port. In this way, the cannula system allows exchange of multiple devices through the access port without requiring additional incision.
In another method, when deployment of multiple medical devices into a vessel or cardiac tissue is necessary, a second access port can be attached to either the cannula or the first access port prior to inserting the cannula into the vascular tissue. For example, during arterial cannulation for cardiopulmonary bypass, a blood filter may be inserted through the first access port, and an occlusion catheter having a balloon occluder may be inserted through the second port into the aorta. The blood filter is expanded to entrap embolic materials, calcium, myocardial tissue debris, or atheroinatous plague, which arise as a result of introducing instrumentation or manipulating tissue during surgery. The balloon occluder is expanded to provide circulatory isolation of the coronary vessels from the peripheral vascular system. The proximal end of the cannula is attached to a bypass-oxygenator machine to deliver oxygenated blood to the aorta. After the cardiopulmonary bypass is established, a surgical procedure can be performed on the heart and/or aorta.
Alternatively, the blood filter and the occlusion catheter can be inserted sequentially through the access ports into the aorta. After completion of the surgical procedure, one or both devices can be removed from the access ports. In situations where continuation of the cardiopulmonary bypass is desired post-operatively due to a patient""s low cardiac output state, the blood filter may be removed, leaving the occlusion catheter and the cannula in the aorta. In this manner, multiple therapies and procedures are employed in combination or independently of each other.
It will be understood that there are several advantages to using the clip-on access port(s) disclosed herein for delivering medical therapies. For example, the access port(s) (1) permit a combination of therapies to be employed through only one incision site, thereby minimizing trauma to the vessel wall, (2) allow multiple devices to be operated in combination or independently, (3) reduce the number of devices used concomitantly, thereby minimizing crowding in the surgical field, (4) can be employed in a variety of cardiac or vascular surgeries, (5) can be used in minimally invasive procedures, (6) can be easily mounted to a standard arterial or venous cannula and hereafter removed, and (7) can be mounted to a modified cannula, such that the port is attached to the cannula in only one orientation.